Metrology and Non-destructive Testing ZFP
Steel and corrosion
Main research interests:
In order to monitor the development of relevant structural properties over time, regular structural inspections are usually the best option. In areas that are difficult or impossible to access, where the usual methods of building diagnosis cannot be used, the use of a suitable sensor system is advantageous. Another area of application is components that require continuous and non-destructive recording of relevant properties, e.g. in the monitoring of drainage measures for W-Cl.
Sensors usually allow continuous monitoring of relevant parameters in order to assess the development of the structure's condition. In addition, this approach offers the advantage of always measuring the temporal development of certain parameters at the same point, namely the sensor position. This eliminates measurement scatter from local differences, which can be not insignificant under certain circumstances. Due to the continuous monitoring, further steps can be planned in time in case of critical changes in the parameters in order to maintain the load-bearing capacity and serviceability of a component.
The aim of a building diagnosis is to determine or monitor the actual condition of a building. In doing so, all the necessary information is collected for the preparation of damage prognoses and maintenance concepts. The condition of a structural component can be determined at specific points in time by means of structural examinations or continuously with the help of monitoring systems, whereby the main focus here is on the corrosion of steel in concrete.
Within the framework of a structural diagnosis, various parameters relevant to durability are determined, depending on the issue, with which the load-bearing capacity and serviceability of a structural component can be assessed.
A wide range of different sensors, measuring devices and data loggers is available for monitoring corrosion-relevant parameters such as corrosion currents, reinforcement potentials or concrete resistances.
The further development of sensors and measurement parameters as well as the development of individual special solutions for specific measurement tasks is one of our main areas of research.
Current research projects are concerned with the development of special corrosion sensors for improved installation in existing structures.
With the help of single-sided magnetic resonance measurement technology, precise depth-resolved profiles of water in porous building materials and organic compounds such as polymers can be measured. Two NMR-MOUSE (Mobile Universal Surface Explorer) with maximum measuring depths of 5 and 25 mm are available for this purpose at the Institute for Building Research. Current research projects include the ageing of polymer materials, the durability of hydrophobic coatings and moisture measurement in concrete and natural stones.
Research into the durability of building materials requires both highly sensitive measurement technology and controlled and accelerated ageing. For artificial ageing, various test set-ups are available at the Institute for Building Research, with which virtually all forms of stress occurring in the environment, such as humidity, radiation, temperature and frost, as well as aggressive gases, can be simulated.
High temperature test
The temperature resistance of building materials is an important material property, not only for fire applications. At the Institute for Building Research, a high-temperature furnace is available for this purpose, with which mechanical tests of test specimens up to 200 mm wide and 1000 mm long can be loaded with up to 10 kN up to a temperature of 1200°C. The furnace is equipped with an optical deformation measurement system. An optical deformation measurement system from GOM is used to measure the deformations that occur during testing at elevated temperatures.
Within the scope of the current research, the temperature dependency or the high-temperature resistance of mortars, concrete and plaster are being investigated.